What is HD Sound?

The phrase HD Sound is used to describe audio where we have taken specific steps in the distribution and transmission chains to maintain the quality and fidelity of the original source material. For online content this generally means three things:

  • The amount of bandwidth reduction has been kept to a minimum by using a high bitrate in the encoder
  • The encoding codec is of a high-quality music type
  • The amount of audio signal processing has been kept to a minimum (e.g. Radio 3 HD Sound uses the AAC-LC codec at 320kbs and has no audio signal processing applied)

Whilst all of our services are now available at the high-quality 320kbs AAC-LC encoding only Radio 3 currently has the signal processing bypassed and so is the only service to broadcast in HD Sound. If you have sufficient bandwidth available, your sound on Radio 3 should automatically default to HD.